1. Field of the Invention
The present invention relates to a printing system having a printer which enters a sleep mode if receives no signal representative of printing data for a predetermined period of time more than a sleep time, and more particularly to a printing system with a printer, capable of always setting a sleep time suitable for variable operating condition of the printer by controlling the record of standby time interval between a print start time in a present printing operation and a print end time in a printing operation executed just before the present printing operation in the printer.
2. Description of Related Art
Heretofore, for one of printers for printing in accordance with the print data transmitted from a personal computer and the like, for example, there has been known a printer capable of entering a sleep mode by cutting off the power supply to a part of a hard ware of the printer if it does not perform a printing operation for more than a preset period.
The sleep mode is an effective function for power saving in printers. Because it can avoid wasted power consumption caused by a toner fixing heater if continuously heated even when the printer does not perform printing for a long time.
The printer with the sleep mode, generally, is arranged so that it is released from the sleep mode on receiving a signal representative of print data from, for example, a personal computer and then starts a warming-up process. It, however the print data is transmitted from the personal computer to the printer in a sleep state, the printer could start a printing operation after a lapse of a remarkably long time from the signal transmit time, so that it takes a long time to complete the printing operation.
To avoid the above problems, for example, Japanese patent application unexamined publication No. 7-251550 discloses an image forming apparatus adapted for reducing power consumption by entering a sleep mode after a definite time from the completion of printing, in which the time T from the completion of printing to the entry in the sleep mode is set based on the interval between the completion of printing and the arrival of a next printing signal. In such the image forming apparatus, the time T to enter the sleep mode is changed based on the signal arriving interval so that the time T is shortened if the arriving interval of printing signal is long or lengthened if the same is short. This apparatus can avoid a long first print time when it is frequently used, and enter a sleep state promptly when it is not much used, resulting in the reduction of power consumption.
In the image forming apparatus mentioned above, although the time T from the completion of printing to the entry in a sleep state is determined based on the interval of the arrival of the next printing signal in consideration of the records of signal arriving intervals, the time T is merely roughly set. For instance, the time T is set to 10 min. for the arriving interval of the next printing signal of more than 30 min., to 15 min. for the signal arriving interval in the range of more than 10 min. and less than 30 min., and to 30 min. for the signal arriving interval of less than 10 min.
In the above way, the time T can not always be set to the most suitable value when the arriving interval of the next printing signal varies every moment according to operating condition of the image forming apparatus. In this regard, the apparatus is desired to flexibly change the time T in correspondence with the signal arriving interval even if it varies from moment to moment so that a first print time be prevented from becoming long and the apparatus promptly enter a sleep mode to thereby reduce power consumption of the apparatus, which increases efficiency.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide a printing system that controls the record of standby time data from a print end time in the printing operation to a print start time in the next printing operation, so that a suitable sleep time be always determined according to an operating condition of the printer even if the condition varies every moment.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a printing system having a printer which enters a sleep mode when it does not receive print data for more than a sleep time, the system comprising means for storing and controlling each standby time value in plural times printing operations, the standby time being a period between a start time of a present printing operation and an end time of a printing operation executed just before the present printing operation, and means for calculating a sleep time based on the standby time values stored in the standby time control means by putting weight on late values among the standby time values stored in the standby time control means.
The above printing system can set a suitable sleep time according to the operation condition of the printer in recent years. Accordingly, the most suitable sleep time can be determined based on the last record of standby time values even if the printer operating condition varies every moment.
According to the second aspect of the present invention, there is provided a printing system having a printer which enters a sleep mode when it does not receive print data for more than a sleep time, the system comprising means for storing and controlling standby time values in plural times printing operations, the standby time being a period between a start time of a present printing operation and an end time of a printing operation executed just before the present printing operation, and means for calculating a sleep time on the basis of the standby time values stored in the standby time control means by considering whether a number of standby time values exceeding a preset standard value, among the standby time values stored in the standby time control means, is larger than a predetermined number.
According to the third aspect of the present invention, there is provided a printing system having a printer which enters a sleep mode when it does not receive print data for more than a sleep time, the system comprising means for storing and controlling standby time values in plural times printing operations, the standby time being a period between a start time of a present printing operation and an end time of a printing operation executed just before the present printing operation, and means for calculating a sleep time on the basis of the standby time values stored in the standby time control means by considering an average value of the standby time values stored in the standby time control means.
According to the fourth aspect of the present invention, there is provided a printing system having a printer which enters a sleep mode when it does not receive print data for more than a sleep time, the system comprising means for storing and controlling standby time values in plural times printing operations, the standby time being a period between a start time of a present printing operation and an end time of a printing operation executed just before the present printing operation, means for judging whether a number of standby time values exceeding a standby time upper limit, among the standby time values stored in the standby time control means, is less than a predetermined number when a sleep time is set between the standby time upper limit and a standby time lower limit, means for calculating an average value of the standby time values when the judgement means determines that the number of the standby time values exceeding the standby time upper limit is less than the predetermined number, and means for calculating a sleep time based on the average value of the standby time values calculated by the average calculating means, the standby time upper limit, and the standby time lower limit.